sharing a drive in network - windows xp / win 7 / vista

1. right click on the drive or folder and select properties .
2. select the share tab.
3. check the share this folder on network
4. enter the share folder name to access it in network .
5. also check allow network users to change my files (only if users need writing rights)

for window 7 and vista users  have security option with user authentication and access rights.